Core barrel



Dec. 21 1926. l,611,.504

R. c. BAKER CORE BARREL Filed Deo. l5, 1925 IN V EN TOR.

Patented Dec. 21, 1926.

y UNITED STAT-ES PATENT OFFICE.

REUBEN e. BAKER, or. coALINGA, eamromvra, AssIGivora To 13A-ima CASING srioE coMrANY, A CORPORATION or CALIFoRNIA.

" come BARREL.

Application led :December 15, 1925'. `serial No. 75,499.

This invention relates to oil well drilling equipment and particularly ertains toan apparatus 'loruse in'taking 'ormation samples or cores of theformation penetrated by the drill. i l Y y Prior to my invention it was .usual prac` tice in drilling a well by the percussion method, to bring the cuttings to the surface by means of a bailer for examination to determine the characteristics of the formation penetrated by the drill. This system proved unsatisfactory principally for the reason that an inaccurate log of the well was obtained.

It is the principal object of the present invention to provide an improved device adapted for use in connection with the percussion system of well drilling and which may be eiiciently employed to obtain accurate samples or cores of a well at frequent intervals.

In carrying out this object into practice I have Vprovided a. hollow drill barrel which may be run in the well at the end of the drill' stein. A hollow core barrel is reciprocably mounted within the lower end of the drill barrel so that vertical recprocation of the latter will driv'e the core barrel over the core so that a sample of the formation being penetrated may be brought to the surface for examination. I also make use of the relative reciprocation of the parts to force-a cleansing fluid around the cutting ends of the tool to clean away the drillings and cuttings so that a clean cut'core will be obtained..

One form which the invention may assume is exemplified in the following description and illustrated by way of example in the accompanying drawings, in which:

Fig. 1 is a view in vertical section through an apparatus embodying the preferred form of the invention. e

Fig. 2 is a similar view of the device disclosing the manner of its operation.

Fig. 3 is a view of the lower end of the device. f

Referring more particularly to theaccompanying drawings, `10 indicates a drill bari rel head having a threaded shank 11 at its upper end by means of which the device may be` connected with a drill stem. The lower end of the drill barrel head 10 is exteriorly threaded and isthreadedly connected with the upper end of a cylindrical drill barrel Bassum 12. The lower end of this drill barrel 12 iS fitted with a drilling shoe 14 which is capable upon -vertical reciprocation of the device to d rill through the .strata encountered in drilling an oil well. The interior diameter of the 'shoe 1.4 is less than that of the barrel 12 so as to form an interiorly projecting annular shoulder 1.5 within the barrel 12 and adjacent its lower end.

leciprocably mounted within the bore of the drill barrel 12 is a cylindrical core barrel 16 which is fitted at its lower end with a shoe 17 having a sharpened lower end. f The: exterior diameter of the core barrel 16 and its shoe 17 is somewhat less than the interiori` diameter of the drilling shoe 14 and simi,- larly the drill barrel 12. This forms an annular passageway between the adjacent surfaces of the two barrels.

At its Lipper end the core barrel- 16 is f1tted with a head member 18 which is larger in diameter than the barrel 16 thereby forming an exteriorly projecting annular shouli der 19. This shoulder 19 is adapted to abut against shoulder 15 when the Vcore barrel is in its lowermost position and thereby prevent removal of the core barrel-frorn the drill barrel without removing the shoe 14 from the latter.

The exterior surface of the core barrel head member 18 is formed with a plurality of longitudinal grooves 20 to permit liquid lodged above the head 18 to pass downwardly through the passage between the barrels and discharge intermediate the cutting edges of the shoes.

It will be noticed from Fig. 1 that the lower end ofthe drill shoe 14 is formed with cutting teeth. Intermediate these cutting teeth the bore of the drill shoe is formed with a plurality of vertical passageways through which the fluid passing downwardly through the passage between the barrels may discharge between the cutting edges of the shoes.

It will'also be noticed that the core barrel 16 is guided both by its head 18 and by reason of its mounting within the drill barrel shoe 1 4. This mounting of the core barrel will hold it in correct axial alignment relative ,to the drill barrel at all times.

One of the features of the present device is the delivery of fluid to the cutting edges of the shoes to clean away the cuttings. This is accomplished by providing radial passageways 21 in vthe drill barrel head 10' which extend invardly from the exterior surface of the headto an interior chamber 22 extendinginwardly from the lower end of the head 10. The lower end of the chamber 22 is normally closed by a. spring' pressed back pressure valve 23, which opens downwardly. This valve is capable of admitting theluid to the upper end of the `bore ofthe drill barrel when the drill barrel is raised relative to the core barrel. lVhen the former is lowered relative to the core barrelthe valve .23g/preK vents return of the fluid through the( head 10 and the fluid is consequently forced downwardly through the passage between the bar rels to a point intermediate the lower edges of the cuttingshoes. This fluid washes away4 the cuttings. l In operation, if it is desired to take a core of a well, the device is connected to the drill stem as described and run in the well. During the running in, the core barrel Willessume its lowermost-position but will remain connected totherdrill barrel due to the abutment of the shoulders 15 and 19. Upon reaching bottom, the drill shoe will commence cutting and the lower end of .the head 10 will pound on the upper end ofthe core barrel head and force lit over the core. As the drill shoe is operated by the percussion method, the drill barrel will be constantly reciprocated relative to the core barrel when in operation and at each stroke will simultaneouslyI cut around the coreV and drive the core barrel over the core thus cut.

At each upward stroke of the drill barrel relative to the core barrel, water will pass through the radial passageways 21 and through the valve 23 and then'ee into the chamber between the head 10 and core barrel head 11. Upon the downward stroke of the v drill barrel, the valve 23 will close and the water or fluid will. be expelled downwardly through the grooves 20 in the head 18 into the passageway between the barrels, and thence through theY vertical grooves in the bore of the drill slice to a point intermediate the cutting edges of the shoes. This keeps the holel cle/anaind'permits a clean cut sample of the formation encountered to be obtained.

Any liquid trapped in the core barrel may discharge through a check valve 24 and radial passageways 25 which lead to the space intermediate the barrels.

As soon as a depth has been penetrated g corresponding to the length of core desired,

ythe entire device is removed from thewell andthe core is extracted by-unscrewing the core barrel shoe from the barrel. 'If necessary, the entire core barrel may be removed from the drill barrel. l To hold the core in place, a loose split ring 27 is mounted interiorly of the core barrel shoe at its lower end.` This ring pinches or shaves ofi' `the cores and-at the same time prevents their removal from the barrel.

From the foregoing rit is manifest that I have provided a device capable of' use in connection with the percussion system of drilling and which may be efliciently employed to take cores or samples ofthe formation encountered at frequent intervals and at a minimum of time and expense.

While l have shown the preferred form of my invention', it isto be understood that various changes in its construction may be made by those skilled in the art without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, what iI claim and desire to secure by Letters Patent is: i

1. A device of` the character described comprising a drill barrel having a closed upper end, means at the upper end of the barrel by which it may be connected with a tool for lowering it and Qperating it within a well, a core barrel mounted within the drill vbarrel and free for a limited amount of axial movement relative thereto, a drilling shoe at the lower end of the drill barrel whereby vertical Ireciprocation of the drill barrel at the bottom of a well will form a core, the upper end of the drill barrel being adapted to strike against the upper end of the core barrel during the rceiprocation of the drill barrel and thereby drive the core barrel over the core formed by the drill barrel, fluid de.- livery means formed intermediate the barrels, and means for delivering fluid through said delivery means and discharge it inter-- mediate the lower ends of the barrels.

2. A device of the character described comprising a drill barrel having aclosed upper end; means at the upperend of the barrel by which it may be connected with a tool for lowering it and operating it within a well, a core barrel mounted within the drill barrel and freel for a limited amount of axial movement relative thereto, a drilling shoe at the lower end of the drill barrel whereby vertical reciprocation of the drill barrel at the bottom of a well will form a core, the upper end of the drill barrel being adapted to strike against the upper end of the core barrel during the reciprocation of the drill barrel and thereby drive the core barrel over the core formed by the drill barrel, fluid delivery means formed intermediate the barrels, and means actuated by the relative reciprocation of the barrels to force fluid through said deliverymeans and discharge it intermediate the lower ends of the barrels.'

3.'A device of the character described comprising a drill barrel having a closed upper end,"means at the upper end of the barrel by which it may be connected with a tool for lowering it and operating it within a well, a core barrel mounted within the drill barrel and free for a limited amount of axial movement relative thereto, a drilling shoe at the lower end of the drill barrel whereby vertical reciprocation of the drill barrel at the bottom of a well will form a core, the upper end of the drill barrel being adapted .to strike against the upper end of the core barrel during the reciprocation of the drill barrel and thereby drive the core barrel over the core formed by the drill barrel, a fluid passageway intermediate the barrels, a check valve for admitting fluid in-v termediate the upper ends of the barrels upon the upward stroke of the drill barrel, said checkvalve closing upon the down- Ward stroke of the drill barrel causing said fluid to be expelled through said passagewav and discharged intermediate the lower -ends of said barrels.

4. AA device of the character described comprising a drill barrel having a closed upper end, means at the upper end of the barrel lby which it may be connected with a 2 tool for lowering it and operating it within a well, a core barrel mounted within the drill barrel and free .for a limited amount of axial movement relative thereto, a drilling shoe at the lower end of the drill barrel whereby vertical reciprocation of the drill barrel at the. bottom of a well will form a core, the upper end of the drill barrel bein adapted to strike against the upper en of the core barrel during the reci rocation of the drill barrel and thereby rive the core barrel over the core formed by the drill barrel, a iuid passageway intermediate the barrels, a check valve for admitting fluid intermediate the upper ends of the barrels upon the upward stroke of the drill barrel, said check valve closing upon the downward stroke of the drill barrel causing saidfluid to be expelled through said passageway and discharged intermediate the Alower ends of said barrels, discharge ports formed in the upper end of the core barrel, a check valve controlling said ports whereb fluid trapped in the core barrel may be ischarged into said passageway intermediate the barrels.

REUBEN C. BAKER. 

